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Species / Anchura Lynnensis

Anchura Lynnensis

  • Anchura ? lynnensis Stephenson, 1941

Original description of Anchura ? lynnensis by Stephenson, 1941:

  • "Shell of medium size, elongate-conical, apical angle not measurable, but the species appears to be more slender than any of the other Texas Navarro species. Whorls 5+, broadly convex to flattish on the sides. The suture appears to be closely appressed and not deeply impressed. The suture is bordered below by a flattish posterior fasciole, 1/3 to 1/4 the total width of the whorl, and the lower edge of this fasciole is marked by a slightly impressed revolving sulcus. Protoconch not preserved. The surface is ornamented with numerous, narrow, moderately prominent, nearly direct axial ribs which are much narrower than the interspaces and which in their trend exhibit a broad, very slight concavity toward the aperture; these ribs cross the posterior fasciole to the suture; the axials number about 19 on the penultimate whorl and 14 on the antepenultimate whorl. The periphery of the body whorl is broadly rounded and the anterior constriction is less abrupt than on most species of the genus; the axials on the body whorl pass down over the periphery but die out quickly on the upper slope of the base. The molds exhibit obscure traces of fine revolving ridges which have been largely destroyed in the process of fossilization. The body whorl is poorly preserved, but the aperture is elongated, and the siphonal canal though not complete appears to be rather long; the inner lip forms a rather thick callus; the outer lip is not preserved."

Locus typicus: 3.7 miles southwest of Campbell, Hunt County, Texas, USA

Stratum typicum: Corsicana Marl, Navarro Group, Maastrichtian, upper Cretaceous

Holotype: incomplete; U.S.N.M. no. 76919; height 51+ mm, thickness approximately 15 mm

Anchura ? lynnensis in Stephenson, 1941; left squeeze of the external mold of the holotype, right internal mold of the holotype

  • Image courtesy The University of Texas at Austin

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